1978697 has 4 divisors (see below), whose sum is σ = 2261376. Its totient is φ = 1696020.

The previous prime is 1978693. The next prime is 1978709. The reversal of 1978697 is 7968791.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1978697 - 2² = 1978693 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1978693) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 141329 + ... + 141342.

It is an arithmetic number, because the mean of its divisors is an integer number (565344).

2^1978697 is an apocalyptic number.

It is an amenable number.

1978697 is a deficient number, since it is larger than the sum of its proper divisors (282679).

1978697 is an equidigital number, since it uses as much as digits as its factorization.

1978697 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282678.

The product of its digits is 190512, while the sum is 47.

The square root of 1978697 is about 1406.6616508599. The cubic root of 1978697 is about 125.5431722921.

The spelling of 1978697 in words is "one million, nine hundred seventy-eight thousand, six hundred ninety-seven".